From 5aa8d484f27883778ccd105e034f8bcd8bfe48a2 Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Wed, 8 Jul 2026 01:33:54 -0700
Subject: hammerspoon: Apply layout changes automatically

Whenever one of the applications that I care about is opened, or when the screen
size changes, apply the layout as specified.
---
 hammerspoon/.hammerspoon/init.fnl | 65 +++++++++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 19 deletions(-)

diff --git a/hammerspoon/.hammerspoon/init.fnl b/hammerspoon/.hammerspoon/init.fnl
index fda2cb0..15640c5 100644
--- a/hammerspoon/.hammerspoon/init.fnl
+++ b/hammerspoon/.hammerspoon/init.fnl
@@ -7,25 +7,52 @@
 (hs.hotkey.bind ["cmd" "alt" "ctrl"] "e" show-window-title)
 (hs.hotkey.bind ["cmd" "shift"] "r" hs.reload)
 
-(let [my-screen (hs.screen.primaryScreen)
-      screen-mode (: my-screen :currentMode)
-      geom [(. screen-mode "w") (. screen-mode "h")]
-      max (. hs "layout" "maximized")]
-  (case geom
-    [3440 1440] (hs.layout.apply
-                 [["Emacs" nil nil (. hs "layout" "left70") nil nil]
-                  ["Wezterm" nil nil (. hs "layout" "right30") nil nil]
-                  ["Glide" nil nil max nil nil]])
-
-    [5120 1440] (hs.layout.apply
-                 [["Glide" nil nil (. hs "layout" "left25") nil nil]
-                  ["Emacs" nil nil (hs.geometry.rect 0.25 0 0.5 1) nil nil]
-                  ["Wezterm" nil nil (. hs "layout" "right25") nil nil]])
-
-    _ (hs.layout.apply
-       [["Glide" nil nil max nil nil]
-        ["Emacs" nil nil max nil nil]
-        ["Wezterm" nil nil max nil nil]])))
+;;; Layout -- Automatically put windows in their place.
+
+(fn apply-layout []
+  (let [my-screen (hs.screen.primaryScreen)
+        screen-mode (: my-screen :currentMode)
+        geom [(. screen-mode "w") (. screen-mode "h")]
+        max (. hs "layout" "maximized")]
+    (case geom
+      [3440 1440] (hs.layout.apply
+                   [["Emacs" nil nil (. hs "layout" "left70") nil nil]
+                    ["WezTerm" nil nil (. hs "layout" "right30") nil nil]
+                    ["Glide" nil nil max nil nil]])
+
+      [5120 1440] (hs.layout.apply
+                   [["Glide" nil nil (. hs "layout" "left25") nil nil]
+                    ["Emacs" nil nil (hs.geometry.rect 0.25 0 0.5 1) nil nil]
+                    ["WezTerm" nil nil (. hs "layout" "right25") nil nil]])
+
+      _ (hs.layout.apply
+         [["Glide" nil nil max nil nil]
+          ["Emacs" nil nil max nil nil]
+          ["WezTerm" nil nil max nil nil]]))))
+
+(fn make-application-watcher []
+  (fn match-application [name event-type application]
+    (print (.. "Application " name " had event " event-type "; compared to " (. hs :application :watcher :launched)
+               "; deciision " (tostring (and (= event-type (. hs :application :watcher :launched))
+                                             (or (= name "Emacs")
+                                                 (= name "Wezterm")
+                                                 (= name "Glide"))))))
+    (when (and (= event-type (. hs :application :watcher :launched))
+               (or (= name "Emacs")
+                   (= name "WezTerm")
+                   (= name "Glide")))
+      (apply-layout)))
+  (hs.application.watcher.new match-application))
+
+(fn make-screen-watcher []
+  (hs.screen.watcher.new apply-layout))
+
+(apply-layout)
+
+(let [watcher (make-application-watcher)]
+  (watcher:start))
+(let [watcher (make-screen-watcher)]
+  (watcher:start))
 
 ;;; Mouse -- Automatically set primary button based on mouse connected.
 
-- 
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